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Proceedings Paper

Growth of fluorescence gold clusters using photo-chemically activated ligands
Author(s): Dinesh Mishra; Fadi Aldeek; Serge Michael; Goutam Palui; Hedi Mattoussi
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Paper Abstract

Ligands made of lipoic acid (LA) appended with a polyethylene glycol (PEG) chain have been used in the aqueous phase growth of luminescent gold clusters with distinct emission from yellow to near-IR, using two different routes. In the first route, the gold-ligand complex was chemically reduced using sodium borohydride in alkaline medium, which gave near- IR luminescent gold clusters with maximum emission around 745 nm. In the second method, LA-PEG ligand was photochemically modified to a mixture of thiols, oligomers and oxygenated species under UV-irradiation, which was then used as both reducing agent and stabilizing ligand. By adjusting the pH, temperature, and time of the reaction, we were able to obtain clusters with two distinct emission properties. Refluxing the gold-ligand complex in alkaline medium in the presence of excess ligand gave yellow emission within the first two hours and the emission shifted to red after overnight reaction. Mass spectrometry and chemical assay were used to understand the photo-chemical transformation of Lipoic Acid (LA). Mass spectroscopic studies showed the photo-irradiated product contains thiols, oligomers (dimers, trimers and tetramers) as well as oxygenated species. The amount of thiol formed under different conditions of irradiation was estimated using Ellman’s assay.

Paper Details

Date Published: 22 April 2016
PDF: 9 pages
Proc. SPIE 9722, Colloidal Nanoparticles for Biomedical Applications XI, 972207 (22 April 2016); doi: 10.1117/12.2212025
Show Author Affiliations
Dinesh Mishra, Florida State Univ. (United States)
Fadi Aldeek, Florida State Univ. (United States)
Serge Michael, Florida State Univ. (United States)
Goutam Palui, Florida State Univ. (United States)
Hedi Mattoussi, Florida State Univ. (United States)

Published in SPIE Proceedings Vol. 9722:
Colloidal Nanoparticles for Biomedical Applications XI
Wolfgang J. Parak; Marek Osinski; Xing-Jie Liang, Editor(s)

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